Centrifugal crude oil separator

ABSTRACT

An oil and gas separator for underwater installation receives crude oil at one end of an octagonal toroidal-shaped container and discharges the centrifugally separated oil and gas at the other end. Supports are designed to facilitate the connection of the separator to a wellhead.

United States Patent [72] inventor Pierre P. Orleu Paris, France 2 I]Appl. No. 876,414

[22] Filed Nov 13,1969

[45] Patented AI. 17, 1971 [73] Assignee Commie Francoise Des PetrolesParis, France [32] Priority Nov. 14, 1968 [33] France [54] CENTRIFUGALCRUDE OIL SEPARATOR [50] FieldolSeareh 55/52 I99, 201,207. I77. [91,205

Primary Examiner-Reuben Friedman Assistant Examiner- R. W. BurksAttorney-Sughrue, Rothwell, Mion, Zinn & MAC PEAK ABSTRACT: An oil andgas separator for underwater installation receives crude oil at one endof an octagonal toroidal- 9hhn" shaped container and discharges thecentrifugally separated [52] US. Cl. 55/203 oil and gas at the otherend. Supports are designed to facilitate [51 Int. Cl. 801d 53/24 theconnection of the separator to a wellhead.

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' F I3 7 i 52 1 I 41 79 tifi CENTRIFUGAL CRUDE OIL SEPARATOR BACKGROUNDOF THE INVENTION enter a separator so as to undergo a degassingoperation. The 1 usual underwater separators consist of a body with agenerally cylindrical shape having a number of deflection plates whosefunction it is to facilitate the release of the enclosed gases throughthe impact of the crude oil against these plates. These apparatusesusually include a certain number of control instruments for the purposeof adjusting the flow rate of the crude, the gas and the degassed oil.

A recently introduced separator has been specifically designed to treatthe crude oil received at the head of a submarine well and containsvarious flow-rate control instruments that are placed in a removableinstrument capsule connected'with the help of a suitable connectingdevice to the separation unit. Generally speaking, the exteriorappearance of this separator does not differ from that of the usualseparators. Its production output is similar to known separator unitsand its installation on the ocean bottom involves the same problems byvirtue of the distance of pipelines of acertain length and by therequired dimensions of the separator. The size of the separator requiresconsiderable support area which makes the operation and servicing of theinstallation under water rather impractical. The output of conventionalhorizon- .tal separators can improve to a certain point as their volumeincreases, however, beyond a certain volume, the resultant gains .inoutput are negated by the installation problems and the desirability ofhaving a compact unit.

SUMMARY OF THE INVENTION An object of this invention thus consists inproviding a separator which is both compact and which provides a largeroutput than the conventional separators. The separator of this inventionis characterized by the fact that the crude and gaseous products arechanneled by the walls of the apparatus in a generally curved direction,thus engendering a centrifugal force to improve the separation. Sincethe resultant output of the separator is greater than the conventionalseparator, it is possible to replace a separator of the same length withthe reduced-volume separator of this invention andconsequently theadvantages of thinner steel plates are possible.

Another object of this invention is to provide a separator whose generaldirection comes in the form of an open ring so that the pipeline systemsfor the entry of the crude oil into the separator and the evacuation ofthe gas and the degassed oil are as close together as possible. This isaccomplished by introducing the pipeline system for the crude oilthrough a wall of the separator practically perpendicular to the generaldirection of the ring formed by the lateral walls of the separator. Thewalls through which the crude oil is introduced will thus constitute oneof the ends of the rings. The gas and the degassed oil will be removedthrough a pipeline system at the other end of the separator whichterminates adjacent the first end. With this arrangement the ring-shapedseparator will incorporate two adjacent ends that enable relatively easyconnections to be made to the three pipeline systems consisting of thecrude, gas and oil to an instrument capsule controlling the flow ratesand levels of the separator.

Another object of the invention is to provide a separator that alongwith its support and the wellhead furnishing the crude oil to be treatedwill constitute a stable and compact structure. This is accomplished byhaving the base of the wellhead constructed in one piece with thesupport of the ringshaped separator and having the ring-shaped separatorsurrounding the head of the well. This arrangement provides a separatorwhich is particularly easy to place in position since the connectionbetween the separator and the wellhead is made removable by arranging,the base of the wellhead, an assembly of radial supports having at theirends supports in the form of a stirrup in order to receive saidring-shapediseparator, the upper part of the ring-shaped wall of theseparator containsattachment means which are articulated arms connectedto the removable attachments fixed on a collar mounted at the upperportion of the wellhead. With this arrangement, an economical, compact,higher yield separator has been constructed offering the advantage ofbeing easily installed around a submarine well or being withdrawn fromit.

The reduced size of such an installation helps eliminate the risk ofcollisions or accidents which'are always possible in the ocean betweenthe submarine installationand maritime vessels or other underwaterequipment. I

Other characteristics and advantages of this invention will appear inthe following specification with reference to the attached drawing inwhich the ring-shaped form of a. separator is disclosed in one form ofthe invention by means of eight cylindrical elements connected to eachother.

IN THE DRAWINGS FIG. 1 shows a plane view of the ring-shaped separatorhaving ends practically cut away and being assembled on a wellhead;

FIG. 2 is a view of the section along line II-II in FIG. 1;

FIG. 3 shows a cross section of the support of the separator along lineIll-III in FIG. 2; and

FIG. 4 shows a cross section of the same support along line IV-IV inFIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the preferred embodiment theseparator has been shown as consisting of two parts, one containing theapparatus for the measurement and control of the various fluids, such ascrude, gas and oil. This part generally being designated by the terminstrument capsule and the other portion receiving the crude from theinstrument capsule in order to perform the'oil-gas separation, and inorder to return the finished products into the capsule. A detaileddiscussion of this arrangement can be found in the French patentapplication filed on Oct. 9, 1968 under Ser. No. PV 169 (240), for:Instrument Capsule for Control of Submarine Petroleum Installation andin U.S. Pat. application Ser. No. 864,997, filed on Oct. 9, 1969.

Although this type of separator is illustrated as the preferredembodiment, it is obvious that this invention could be illustrated withfor example a derived separator of the conventional type.

The wellhead, emerging from the ocean bottom has been designated byreference No. l in FIGS. 1 and 2. The pipeline system 2 moves the crudetowards a fixed pipe 3 shown in docket lines, and from there towards apipeline 4 of a mobile piece 5, capable of turning around its axis ofrevolution. For greater clarity, the invention has been illustrated inthe drawings with the instrument capsule containing the prolongedpipelines, respectively the pipes 4, 6, 7, 8, 9 and 10 of piece 5, alongwith the fixed piece 11, constituting the connecting device serving forthe connection of the instrument capsule, not shown.

After passage through the instrument capsule. the crude is moved intothe separator by pipeline systems 8, l2 and I3.

Pipeline system 13 penetrates into the separator through its extremesurface 14, shown in cross section in the drawing and connected by awelded connected element 15, similar to the connection more clearlydisclosed at 16, to a first cylindrical section 17. The separator ofthis invention has a general shape of a ring that is obtained in theillustrated drawings by the juxtaposition of elements such as 18. Theseelements are cylinders with a circular cross section whose includedbases are vertical and symmetrical with respect to a circular crosssection. It is thus easy to connect any two successive identicalelements l8 and 19 along sections such as 20.

In the illustrated embodiment, the separator consists of sevencylindrical sections whose plane projection constitutes seven elementsof an octagonal crown, where the last element contains the pipes of theseparator. Thus, the crude that arrives via pipeline system 13 isintroduced into the interior of the ring-shaped separator, and undergoesintensive centrifugal action that helps promote the degassing of thefinal products. The result is that for one and the same production ofdegassed oil over the same length of a conventional separator, the crosssection of the ring-shaped separator may be reduced and consequentiallyit is possible to utilize thinner plates of steel.

At the end of the separator process, the gases are collected in theupper portion of the separator by pipeline system 21, connected to theextreme surface 22. The gas is moved along by pipeline system 7 to theinstrument capsule and passes through pipelines l and 23 from which itmay be directed toward a torch. The degassed oil is collected in thelower portion of surface 22 by pipeline systems 24 and 9 and it is movedfrom there to the instrument capsule from which it emerges throughpipelines 6 and 25 in order to supply the proper pipeline system.

A manhole 26 may be provided at the end 22 of the separator. Likewise,the cylindrical element 27, connecting the extreme sections of theseparator, incorporates a manhole 28.

Arms 29, 30 and 31 illustrated in FIG. 1, are arranged radially aroundthe wellhead and serve as supports for stirrups 32, as shown in FIGS. 2and 3. In the illustrated embodiment these stirrups are welded on armssuch as 30, as illustrated in FIG. 3. The arm 33, as shown in FIG. 4,reveals a disconnecting device 34 making it possible to support theconnector 11 as shown in FIG. 2.

Arms 29, 30, 31 and 33 are held at the base of wellhead l by collar 35.The upper edge of the collar 35 being supported on collar 36 of the baseof the wellhead. Collar 35 is attached by screwing it tightly on collar37 with the help of bolts and nuts, not shown here.

The separator rests on stirrups 32, and the upper portion of the wall ofthe separator is connected to arms 38 through 41 that are articulated onattachments 42-45. The ends of these arms are attached to theattachments mounted on a collar made up of elements 46 and 47,surrounding the upper portion of the wellhead and kept tightly screwedby nuts and bolts.

The advantage of this arrangement is that it greatly facilitates theplacement of the separator since the separator can be lowered above thewellhead while being suspended with the help of articulated arms 38-4l.While the separator rests on stirrups 32, and when connector 11 rests inits housing, the elements 46 and 47 can be connected around the upperpart of the wellhead. It is clear that numerous modifications can beimplemented in the above-described invention. For example, the floorconstituted by tubes 48, FIG. 1, would be eliminated and the apparatusincluded in the instrument capsule could be installed in the ring-shapedseparator. Under these conditions, pipeline system 2, coming from thewellhead, would be directly connected to pipeline system 13. Further,oil pipeline system 24 would be connected to pipeline system 25, and gaspipeline system 21 would be connected to pipeline system 23. Appropriatevalves could be added on these pipeline systems.

I claim:

1. A compact separator for separating gas and oil from crude receivedfrom a wellhead comprising:

a housing with an opening for receiving the crude, a closed curvedchannel means in the fonn of an open ring lying substantially in ahorizontal plane and connected to the opening for creating a centrifugalforce with the flowing crude to encourage separation of gas and oil andoutput means connected to the open ring for separately removing the oiland gas.

2. A separator as in claim 1, where the open ring ends are closed andone end of the ring receives the crude and the other end discharges theoil and as.

A separator as 1n claim including an infrastructure which is rigidlyconnected to the wellhead, the ring-shaped separator surrounding thewellhead.

4. A separator as in claim 1 including securing means located on theupper portion of the housing, a collar and arms articulated from thesecuring means to the collar attached to the wellhead.

5. A separator as in claim 1 including a removable and rigid connectionwith the upper portion of the wellhead for supporting the separatorhousing and a rigid support at the base of the wellhead for supportingthe separator housing about the wellhead.

6. A separator as in claim 1, where the ring consists of cylindricaljuxtaposed sections.

7. A separator as in claim 1, where the housing consists of an assemblyof tubular sheaths connected around a head of a well to form acontinuous tubular envelope, one of the sheaths including a manhole foraccess to the interior of the envelope, the ring separator having endsthat terminate adjacent the manhole, securement means fixed to the upperportion of the housing, a collar screwed to the head of the well, armsarticulated from the collar to the securement means, and a separatorsupporting means attached to the base of the wellhead.

8. A compact separator for separating gas and oil from crude receivedfrom a wellhead comprising;

a housing with an opening for receiving the crude, a closed curvedchannel means in the form of an open ring connected to the opening forcreating a centrifugal force with the flowing crude to encourageseparation of gas and oil and output means for separately removing theoil and gas, whereby the open ring ends are closed and one end of thering receives the crude and the other end discharges the oil and gasthrough separate conduits.

9. A separator as in claim 8 including an infrastructure which isconnected to the wellhead, the ring-shaped separator surrounding thewellhead and supported by the infrastructure.

2. A separator as in claim 1, where the open ring ends are closed andone end of the ring receives the crude and the other end discharges theoil and gas.
 3. A separator as in claim 1, including an infrastructurewhich is rigidly connected to the wellhead, the ring-shaped separatorsurrounding the wellhead.
 4. A separator as in claim 1 includingsecuring means located on the upper portion of the housing, a collar andarms articulated from the securing means to the collar attached to thewellhead.
 5. A separator as in claim 1 including a removable and rigidconnection with the upper portion of the wellhead for supporting theseparator housing and a rigid support at the base of the wellhead forsupporting the separator housing about the wellhead.
 6. A separator asin claim 1, where the ring consists of cylindrical juxtaposed sections.7. A separator as in claim 1, where the housing consists of an assemblyof tubular sheaths connected around a head of a well to form acontinuous tubular envelope, one of the sheaths including a manhole foraccess to the interior of the envelope, the ring separator having endsthat terminate adjacent the manhole, securement means fixed to the upperportion of the housing, a collar screwed to the head of the well, armsarticulated from the collar to the securement means, and a separatorsupporting means attached to the base of the wellhead.
 8. A compactseparator for separating gas and oil from crude received from a wellheadcomprising; a housing with an opening for receiving the crude, a closedcurved channel means in the form of an open ring connected to theopening for creating a centrifugal force with the flowing crude toencourage separation of gas and oil and output means for separatelyremoving the oil and gas, whereby the open ring ends are closed and oneend of the ring receives the crude and the other end discharges the oiland gas through separate conduits.
 9. A separator as in claim 8including an infrastructure which is connected to the wellhead, thering-shaped separator surrounding the wellhead and supported by theinfrastructure.